If you don't understand the directions that are linked to, don't even try to install rockbox. It's not the easiest thing in the world to do and it would be quite bad if people started screwing up their sansa's left and right.

I just install Rockbox on my Sansae260, and he is worked!
To Install Rockbox you must
1. Download this rockbox.rar
2. Unarchive rockbox.rar in parent directory in you sansa in MSC mode
3. Disconnect Sansae from PC

Folks, don't install rockbox unless you know how to go into recovery mode and put the original firmware back in. It does not even have sound yet, so there is really not point in trying it unless you want to help with development (if you know C). Most importantly of all, don't ask the developers how to recover or put rockbox in, as they have explained this numerous times on numerous forums; just use the search feature! If you keep bugging them, chances are they won't post updates and will keep development information closed so that they don't have to deal with a bunch of people always asking the same questions.